Comments

I'd go with Civ V. It has way bigger fan base and way more mod support. The mods are half the fun and can really change and enhance gameplay. Endless legend is cool and fun, but Civ is the game of that genre and it just has way more going for it. Plus it's cheaper if you get it during the sale like $12.50 for the complete pack. But make sure you get the complete pack, all the stuff it adds to the game is pretty awesome.

TL:DW They both are very similar in both pros and cons aside from obvious theme differences (sci-fi vs fantasy.) They may be a bit more of a brick wall of information then some other Civ & Civ-like games. And like Karma said their overall potential right now isn't fully realized just yet. I would say go with whichever looks the way you enjoy more or which has the least amount of little things you don't enjoy compared to the other. Civ Beyond Earth would likely have the better lasting potential due to the history of other Civilization games. You'd probably also more liekly get to play with other IC people on Civ since they are likely to go with that since they probably know about it compared to Endless Legend.